The invention relates to a heat-dissipating mechanism for a motor, and in particular to a heat-dissipating mechanism for a motor applied to a fan.
Motors are commonly used in various fields. For example, motors are often disposed in fans to assist in heat dissipation. The fans can be roughly classified as centrifugal and axial-flow types. Motors enable rotation of blades of both the centrifugal and axial-flow fans, achieving active heat dissipation.
FIG. 1A is a schematic perspective view of a conventional centrifugal fan 10a. In the centrifugal fan 10a, a rotor 12a is driven by a motor inside thereof (not shown) and multiple blades 14a are connected to the rotor 12a. When the rotor 12a rotates, the blades 14a connected thereto rotate accordingly, circulating air and thereby achieving heat dissipation.
FIG. 1B is a schematic perspective view of a conventional axial-flow fan 10b. Similarly, in the axial-flow fan 10b, a rotor 12b is driven by a motor (not shown) and multiple blades 14b are connected to the rotor 12b. When the rotor 12b rotates, the blades 14b connected thereto rotate accordingly, circulating air and thereby achieving active heat dissipation. Additionally, the axial-flow fan 10b includes a fan frame 16b, providing more concentrated airflow and enhancing heat dissipation.
Nevertheless, during the operation of the aforementioned fans, heat is inevitably generated in the rotors due to high-speed rotation and heat generally accumulates in the rotors. When the fans operate over a long period of time, the motors thereof are easily damaged due to high temperature caused by the heat accumulated in the rotors. The lifespan of the fans is thus reduced.
To overcome the aforementioned problems, other conventional centrifugal and axial-flow fans are disclosed. FIG. 1C is a schematic perspective view of another conventional centrifugal fan 10c. FIG. 1D is a schematic perspective view of another conventional axial-flow fan 10d. Similarly, in the centrifugal fan 10c, a rotor 12c is driven by a motor (not shown) and multiple blades 14c are connected to the rotor 12b. When the rotor 12c rotates, the blades 14c connected thereto rotate accordingly, achieving active heat dissipation. Specifically, a plurality of openings 18c is formed on the rotor 12c. When the rotor 12c rotates, hot air within the rotor 12c can be discharged via the openings 18c. Therefore, heat does not accumulate in the rotor 12c and does not cause damage to the motor. Similarly, in the axial-flow fan 10d, a rotor 12d is driven by a motor (not shown) and multiple blades 14d are connected to the rotor 12d. Additionally, a plurality of openings 18d is formed on the rotor 12d, and the rotor 12d and blades 14d are disposed within a fan frame 16d. When the rotor 12d rotates, the blades 14d connected thereto rotate accordingly. Heat generated by the rotor 12d is discharged via the openings 18d and does not accumulate therein the rotor 12d. 
Although the heat generated by the rotors can be discharged via the openings, external particles, dust or moisture also enter the rotors via the openings. When the centrifugal fan 10c and axial-flow fan 10d operate, dust, minute particles or moisture can easily enter the rotors 12c and 12d via the openings 18c and 18d, respectively. As the result, the rotating shafts of the motors may be obstructed by the external particles and the motors thereby damaged.